1) Field of the Invention
This invention relates generally to fabrication of bit lines and more particularly to the fabrication of a Magnetoresistive head (MR) for a Magnetic disk drive and more particularly to a method for forming a passivation layer over a MR sensor layer.
2) Description of the Prior Art
The prior art discloses a magnetic transducer referred to as a magnetoresistive (MR) sensor or head which has been shown to be capable of reading data from a magnetic surface at great linear densities. A MR sensor detects magnetic field signals through the resistance changes of a read element made from a magnetoresistive material as a function of the amount and direction of magnetic flux being sensed by the element.
Current MR heads are manufactured by using a lift-off process to deposit lead layers and define reader track. See e.g., U.S. Pat. No. 5,658,469(Jennison) that shows a lift-off method for improving the photoresist lift-off block shape.
Numerous prior art MR sensors have been developed, and these prior art MR sensors have been effective to meet prior art requirements. However, the drive toward increased recording density has led to the requirement for narrower recording tracks and increased linear recording density along the track. The small MR sensors which are necessary to meet these requirements cannot be made with the use of the prior art techniques.
The importance of overcoming the various deficiencies noted above is evidenced by the extensive technological development directed to the subject, as documented by the relevant patent and technical literature. The closest and apparently more relevant technical developments in the patent literature can be gleaned by considering RE34,099(Krounbi et al.) that shows an thick insulating layer over a MR sensor.
U.S. Pat. No. 5,256,249(Hsie et al.) discloses a method for forming a MR sensor having a track wide oxide layer overlying the MR sensor.
U.S. Pat. No. 5,658,469(Jennison) shows a method for improving the photoresist lift-off block shape to form a consistent undercut.
U.S. Pat. No. 5,568,335(Fontana et al.), U.S. Pat. No. 5,491,600(Chen et al.) and U.S. Pat. No. 5,747,198(Kamijima) show a photoresist lift-off processes to form a MR heads.